The Green Builder Coalition has been working hard on their Water Efficiency Rating Score — the WERS — for homes. The inaugural WERS training happened in Santa Fe, New Mexico, in March. I was in that class, and I learned a lot.
The program has been in development for the past couple of years. Now it’s ready for prime time.
How the program works
Like the HERS Index for energy efficiency, the WERS is a way to put a number on a home’s water efficiency. It’s a water use modeling tool that allows you to compare one house to another. You have to put in all the data for a home’s water use, and the tool gives you a number, generally between 0 and 100. As with the HERS Index, lower is better. A WERS of zero means you’ve got a net zero water house. That happens only when you capture rainwater.
One of the things you do is measure structural waste. That’s the amount of water that comes out of a faucet or shower while you’re waiting for the hot water to arrive. The photo below (see Image #2 at the bottom of the article) shows the equipment we used in the class to measure water for a shower. It consists of a Ziploc bag, a piece of PVC pipe with a couple of fittings to hold the bag, and a measuring cup. This setup works really well!
When you’re doing a field inspection, you go around and fill out the checklist. The screenshot in Image #4 (below) shows part of the checklist for indoor water efficiency. The first thing you do is put a pressure gauge on a faucet, turn off the water supply to the house, and see if the pressure drops.…